Recently, many efforts are made to research and develop various coding schemes and methods for digital audio signals and products associated with the various coding schemes and methods are manufactured.
And, coding schemes for changing a mono or stereo audio signal into multi-channel audio signal using spatial information of the multi-channel audio signal have been developed.
However, in case of storing an audio signal in some recording media, an auxiliary data area for storing spatial information does not exist. So, in this case, only a mono or stereo audio signal is reproduced because the mono or stereo audio signal is stored or transmitted. Hence, a sound quality is monotonous.
Moreover, in case of storing or transmitting spatial information separately, there exists a problem of compatibility with a player of a general mono or stereo audio signal.